There's now a national security angle to the Russian whistleblower who mysteriously dropped dead while jogging

The long-awaited inquest into the mysterious death of a Russian
whistleblower has been delayed because the UK government is
trying to stop certain documents related to the case being made
public.

Alexander Perepilichny died while jogging near his home in Surrey
four years ago.

Traces of a deadly chemical compound, which is found in a
poisonous plant known as heartbreak grass, were found in his
stomach, according to evidence in a pre-inquest hearing.

Prior to his sudden death, Perepilichny had been assisting
Hermitage Capital, an investment fund, in exposing an alleged
Russian laundering operation worth millions of dollars, according to the Financial Times.

The inquest into the whistleblower's death was due to get
under way at a coroners' court in Woking, Surrey, next Monday.
However, it has been pushed back until at least March next year
due to a legal wrestling match over documents which the
government argues would undermine national security if made
public.

Richard Travers, the coroner who was set to oversee the
inquest, said at a hearing on Tuesday that he had "no choice" but
to delay proceedings because the government wanted to secure
Public Interest Immunity status (PII) for sensitive documents
directly related to the investigation
into Perepilichny's death.

PPI status is a rarely-used legal apparatus which is
applied in cases where the disclosure of sensitive documents
would pose a clear threat to national security. Henrietta Hill, a
barrister for Hermitage Capital, claimed the documents in
question were "plainly relevant" to the "central question" of
whether Perepilichny was murdered.

The grave of murdered
ex-KGB agent Alexander Litvinenko is seen at Highgate Cemetery in
London, Britain, January 21, 2016.Toby Melville/Reuters

Perepilichny and Litvinenko's cases are also similar because both
were involved in major efforts to expose corruption among Russian
elites immediately before their deaths. The latter had been due to give evidence to a
Spanish prosecutor relating to Vladimir Putin's links to
organised crime just a week after he was poisoned.